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Biomedical subjects

R Fayer

Publications and source records attributed to R Fayer.

At least 163 records · Page 9Linked to original sources
PubMed1980

Sarcocystosis in cattle in Kentucky.

Sarcocystosis was diagnosed in 41 eighteen-month-old heifers and steers. Clinical signs included anorexia, severe weight loss, nervousness, hypersalivation, lameness, and hair loss on the extremities. Hair loss was noticed especially at the end of the tail, where there was complete loss of the switch, giving the animals a "rat-tail" appearance. Consistent gross changes observed at necropsy of four affected animals included generalized lymphadenopathy, erosions and ulcerations in the oral cavity and esophagus, and severe laminitis. Microscopically, young cysts of Sarcocystis sp were disseminated in the heart, skeletal muscle, and brain. Ultrastructural examination indicated that the cysts were young because they contained metrocytes. Affected animals had moderate to severe nonsuppurative myocarditis and myositis, with focal degeneration of myofibers and infiltration by macrophages, lymphocytes, and plasma cells. Indirect hemagglutination of sera from 19 animals revealed a mean antibody titer of 1:24,000 against Sarcocystis bovicanis antigen. Epidemiologic investigation incriminated resident farm dogs that had been housed in a farm hayloft as the source of infection. Hay contaminated with sporocysts in dog feces was thought to have been fed to the heifers and steers.

Animals↗
PubMed1980

Amprolium for prophylaxis of ovine Sarcocystis.

The efficacy of amprolium against clinical sarcocystosis resulting from Sarcocystis ovicanis was determined in two experiments involving 40 lambs. In each experiment, four lambs were used in each of five test groups--uninoculated unmedicated, inoculated unmedicated, uninoculated medicated (100 mg/kg), inoculated medicated (100 mg/kg), and inoculated medicated (50 mg/kg). Amprolium was provided as a feed additive to each medicated group for 31 days beginning 1 day before oral inoculation with 100,000 S. ovicanis sporocysts. Data from deaths, body temperatures, weight gains, serum protein levels, hematocrits, hemoglobin values, LDH and SGOT values, postmortem examinations, and histological examinations indicated that amprolium at both levels tested reduced the number of deaths and severity of clinical signs of sarcocystosis in experimentally infected lambs as compared with unmedicated controls.

Amprolium↗
PubMed1979

Transmission of Sarcocystis suihominis from humans to swine to nonhuman primates (Pan troglodytes, Macaca mulatta, Macaca irus).

Sporocysts of Sarcocystis suihominis obtained from human feces were used to infect swine. Heart, tongue, and skeletal muscle from experimentally infected and noninfected control swine were fed via stomach tube to nonhuman primates including chimpanzees (Pan troglodytes), rhesus monkeys (Macaca mulatta), and cynomolgus monkeys (Macaca irus). All primates fed infected swine tissues shed sporocysts beginning 13 to 15 days postinfection and were still shedding sporocysts at the conclusion of the experiment, 30 days postinfection. Rhesus and cynomolgus monkeys were fed infected swine tissues a second time and shed sporocysts. All primates remained in good health throughout both experiments and exhibited no unusual clinical signs as a result of infection.

Animals↗
PubMed1979

Pathophysiological changes in urine and blood from calves experimentally infected with Sarcocystit cruzi.

Two 8-week experiments were conducted to determine the relationships between nutritional stress and pathophysiological changes in male Holstein calves infected with Sarcocystis cruzi. Calves were infected by oral inoculation with 200 000 S. cruzi sporocysts. In the first experiment weight gain reduction was greatest in inoculated calves during weeks 4 and 5 after inoculation. Feed intake was reduced during the 5th week. Erythrocyte count was reduced during week 5 and haemoglobin was reduced during week 6. The 24-h excretion of urinary and urea nitrogen from the inoculated calves was increased by treatment. In the 2nd experiments, both the feed-restricted and inoculated calves lost weight during weeks 4 and 5; feed intake was lower from week 5 to 8 inclusive. Urine volume from inoculated calves was lower during week 8. Lower urine excretions of sodium and potassium resulted from S. cruzi inoculation. There was a non-significant trend for higher urinary zinc excretion in the inoculated group during week 4. Urine nitrogen excretion from inoculated calves was higher during week 6. The urinary excretion of 3-methylhistidine from the inoculated calves was higher during week 4 and excretion of guanine was higher during weeks 4, 5 and 8. S. cruzi has several specific pathophysiological effects on calves beyond those induced by nutritional stress.

Animals↗
PubMed1979

Sarcocystis transmitted by blood transfusion.

Merozoites were found in blood smears from calves, lambs, and pigs exhibiting signs of acute sarcocystosis after oral infection with sporocysts of Sarcocystis bovicanis, Sarcocystis ovicanis, and Sarcocystis suihominis. In each of 3 experiments, whole blood containing merozoites was transfused from an infected host to 2 uninfected recipients of the same species; 2 additional animals of the same species served as uninfected nontransfused controls. The bovine, ovine, and porcine donors all died of acute sarcocystosis. Clinical signs of sarcocystosis were not seen in any transfusion recipients or controls. All recipients and controls were killed and histologic specimens of esophagus, diaphragm, heart, skeletal muscle, and tongue were examined microscopically. Large numbers of intramuscular cysts were present in transfusion recipients, whereas few or no cysts were present in controls, indicating that S. bovicanis, S. ovicanis, and S. suihominis had been transmitted between intermediate hosts of the same species by blood transfusion.

Animals↗
PubMed1978

Sheep experimentally infected with Sarcocystis from dogs. II. Abortion and disease in ewes.

This is the first study of Sarcocystis-induced abortion in sheep. Eleven pregnant ewes were experimentally inoculated with 50,000, 100,000, or 500,000 Sarcocystis ovicanis sporocytis from dogs. Eight ewes either aborted, died, or became moribund before term; they produced 15 fetuses, 11 of normal appearance and 4 necrotic. No evidence of intrauterine transmission was obtained. All infected ewes became anemic, inappetent, and lost weight. Ewes inoculated with the greatest numbers of sporocysts exhibited the most striking signs of acute illness. At necropsy of acutely ill ewes the heart was the most severely affected organ, appearing nearly black as a result of hemorrhagic pancarditis. Less hemorrhage was seen in the kidney, liver, spleen, and skeletal muscles. Microscopically, schizonts were found in capillary endothelial cells of most organs 24 to 33 days after inoculation. Ewes surviving the acute illness appeared generally unthrifty and exhibited the additional signs of wool breaking, and nervous disturbances. At postmortem, the heart and kidneys of these ewes were moderately hemorrhagic, and the adrenal glands and mesenteric lymph nodes were enlarged. Microscopically, sarcocysts were found in the heart, diaphragm esophagus, tongue, skeletal and eye muscles, cerebellum, and cerebrum.

Abortion, Veterinary↗
PubMed1978

Fine structure of immature cysts of Sarcocystis cruzi.

Sarcocystis cruzi forms cysts in striated muscle of the bovine host following schizogony. The fine structure of the immature cyst within muscle fibers of the ventricular myocardium was studied in relation to its development and to the multiplication of parasites within it. The young cyst is enclosed by a cyst wall containing numerous small protuberances. Metrocytes within the cyst are irregular in shape and are separated from each other and the cyst wall by a thin layer of ground substance. The parasite multiplies by endodyogeny within the metrocyte. As the cyst enlarges, the host muscle fiber is disrupted and large protrusions are present in the cyst wall.

Animals↗
PubMed1977

Sarcocystis leporum in cottontail rabbits and its transmission to carnivores.

Muscle from Sarcocystis-infected cottontail rabbits (Sylvilagus floridanus) was fed to coccidia-free cats (Felis domestica) and dogs (Canis familiaris). Only cats became infected and shed sporocysts in their feces. The prepatent period ranged from 10 to 25 days and the patent period from 3 to 46 days. Sporocysts were fully sporulated when shed. They contained 4 sporozoites and a coarse granular residuum and averaged 9.4 by 13.6 micron (N=55). Doses of 200-75,000 sporocysts were orally administered to 5 domestic rabbits (Oryctolagus cuniculus). Domestic rabbits did not become infected, suggesting a strict host specificity for the intermediate host S. floridanus.

Animals↗
PubMed1977

Serologic test for antibody to Sarcocystis in cattle.

Soluble antigen was prepared from Sarcocystis zoites obtained from heart muscle of a bovine inoculated with sporocysts from canine feces and killed 120 days after infection. The antigen was used in an indirect hemagglutination (IHA) test and an agar gel diffusion test to detect antibody to Sarcocystis in experimentally infected cattle. IHA serum titers began to rise 30 to 45 days after infection and reached levels up to 1:39,000 90 days after infection. Sera collected under field conditions from 21 dairy cows had IHA titers ranging from 1:54 to 1:486. Since all cows appeared in good health, titers of 1:486 or less can probably be considered nonsignificant with regard to diagnosis of clinical disease. No positive Sarcocystis IHA titers were obtained with human sera previously found to be IHA positive for toxoplasma, indicating a lack of cross reactivity between antigens. Precipitins in the agar gel diffusion test appeared 30 days postinoculation and became very pronounced at 65 to 90 days.

Animals↗
PubMed1977

Sheep experimentally infected with sarcocystis from dogs. I. Disease in young lambs.

Eight Polled Dorset lambs were orally inoculated with Sarcocystis ovicanis sporocysts. Two lambs that received 100,000 or 200,000 sporocysts became clinically ill, recovered, and were killed 67 and 88 days after inoculation (DAI). Numerous intramuscular cysts were found in their skeletal and cardiac muscles. Three lambs received 100,000 sporocysts, three lambs received 1 million sporocysts, and three lambs received no sporocysts. After an acute clinical illness characterized by anemia, inappetence, weight loss, fever, and reduced serum protein, all lambs that received 100,000 sporocysts died 27 to 29 DAI and all that received 1 million sporocysts died 24 or 25 DAI. Hemorrhage involving the striated muscle and visceral organs was the most apparent gross lesion. The heart appeared most severely affected. Schizonts were found in vascular endothelial cells of all six inoculated lambs. Uninoculated lambs remained healthy, and neither lesions nor parasites were found in any tissues. Dogs fed tissues containing S. ovicanis cysts produced sporocytes 11 to 37 days after feeding; cats fed similar stages produced no sporocysts. Dogs fed tissues containing schizonts produced no sporocysts.

Animals↗
PubMed1977

Production of Sarcocystis cruzi sporocysts by dogs fed experimentally infected and naturally infected beef.

Twenty-one coccidia-free dogs were fed either experimentally infected or naturally infected beef in 4 experiments. The pretreatment period ranged from days 9 to 33; 7 dogs shed their first sporocysts on day 12. The full length of the patent period was not determined because most dogs were still shedding sporocysts when experiments ended on days 40 and 60. Although the patent period was long, sporocysts were not shed continuously; the total number of days sporocysts were actually shed ranged from 3 to 40. The average number of sporocysts shed by dogs fed 454 to 908 g of beef ranged from 861,000 to over 20 million. Most sporocysts were shed from days 15 to 30; peak numbers were shed on days 23 and 24. Average peak numbers ranged from 145,000 to 408,400 sporocysts. Such data can be applied to facilitate collection of sporocysts in the laboratory or to estimate the potential for transmission of infective organisms under field conditions.

Animals↗
PubMed1977

Changes in serum and plasma proteins and in IgG and IgM antibodies in calves experimentally infected with sarcocystis from dogs.

Fifteen calves were used in three experiments to determine changes in serum and plasma proteins and IgG and IgM levels after oral inoculation with Sarcocystis sporocysts from dogs. Total serum or plasma protein levels in inoculated calves decreased during the acute phase of infection (4 to 5 weeks after inoculation) and then increased and became greater than the levels of control calves 7 to 8 weeks after inoculation. The initial decrease in total protein reflected reduced serum albumin and the subsequent increase reflected increased immunoglobulin levels. Immunoglobulin levels increased in both IgM and IgG fractions. Specific antibody activity against Sarcocystis antigen was 6 to 9 times greater in the IgM than in the IgC fraction 5 weeks after inoculation, but IgG activity became approximately 17 to 27 times greater than IgM activity 10 to 13 weeks after inoculation.

Alpha-Globulins↗